Three Championship games on 26 December and five in League Two have been called off because of Covid-19 cases.
Cardiff City v Coventry City, Stoke City-Barnsley and Reading-Peterborough have been postponed in the second tier.
Five scheduled matches in League Two have also already been called off.
The English Football League says "there is optimism that disruption can be minimised" and confirmed that league, Carabao Cup and Papa John's Trophy ties can continue "where safe to do so".
League Two leaders Forest Green, who have now suffered three successive postponements, head the list of five games called off so far in the fourth tier.